Bad news for chocolate. Raises heart rate,
otherwise nothing. :-(


Am J Clin Nutr. 2008 Apr;87(4):872-80.
A double-blind, placebo-controlled, randomized
trial of the effects of dark chocolate and cocoa
on variables associated with neuropsychological
functioning and cardiovascular health: clinical
findings from a sample of healthy, cognitively
intact older adults.
Crews WD Jr, Harrison DW, Wright JW.
Virginia Polytechnic Institute and State
University, Blacksburg, VA 24506, USA.

BACKGROUND: In recent years, there has been
increased interest in the potential health-
related benefits of antioxidant- and
phytochemical-rich dark chocolate and cocoa.

OBJECTIVE: The objective of the study was to
examine the short-term (6 wk) effects of dark
chocolate and cocoa on variables associated
with neuropsychological functioning and
cardiovascular health in healthy older adults.

DESIGN: A double-blind, placebo-controlled,
fixed-dose, parallel-group clinical trial was
used. Participants (n = 101) were randomly
assigned to receive a 37-g dark chocolate bar
and 8 ounces (237 mL) of an artificially
sweetened cocoa beverage or similar placebo
products each day for 6 wk.

RESULTS: No significant group (dark chocolate
and cocoa or placebo)-by-trial (baseline,
midpoint, and end-of-treatment assessments)
interactions were found for the
neuropsychological, hematological, or blood
pressure variables examined. In contrast, the
midpoint and end-of-treatment mean pulse rate
assessments in the dark chocolate and cocoa
group were significantly higher than those
at baseline and significantly higher than
the midpoint and end-of-treatment rates in
the control group. Results of a follow-up
questionnaire item on the treatment products
that participants believed they had consumed
during the trial showed that more than half
of the participants in both groups correctly
identified the products that they had
ingested during the experiment.

CONCLUSIONS: This investigation failed to
support the predicted beneficial effects
of short-term dark chocolate and cocoa
consumption on any of the neuropsychological
or cardiovascular health-related variables
included in this research. Consumption of
dark chocolate and cocoa was, however,
associated with significantly higher pulse
rates at 3- and 6-wk treatment assessments.